Hotfix of the last update

api/serializers/ticket.py

@@ -48,7 +48,7 @@ class TicketStatusSerializer(BaseTicketSerializer):
 
     def validate_status(self, status):
         valid_statuses = self.get_available_statuses(self.instance)
-        if valid_statuses and status not in valid_statuses:
+        if not valid_statuses or status not in valid_statuses:
             raise serializers.ValidationError("Invalid value for the status field")
         return status